Air compressor with self contained cooling system

ABSTRACT

Provided is a self-contained, closed-loop cooling system for an air compressor, and a method of controlling a temperature of the compressor. The air compressor provides compressed air to an associated system. The air compressor includes a passage for a flow of coolant therethrough. A pump pumps an input flow of coolant into the air compressor, and a heat exchanger cools an output flow of coolant from the air compressor. Fluid delivery lines connect the air compressor, the pump, and the heat exchanger in a closed loop configuration, such that the coolant is not subject to contact with atmospheric air or other systems. The cooling system is associated solely with the air compressor for cooling its parts.

BACKGROUND

1. Field

The present invention is generally related to a cooling system for anair compressor.

2. Description of Related Art

Using one or more locomotives in a train to move railroad freight orpassenger cars is well known. Typically, locomotives are manufactured bycompanies such as Electro-Motive Diesel, Inc. (“EMD”) or GeneralElectric (“GE”) to meet standardized designs, with only minor changes indetails possible, if specified by the locomotive customer as a purchaserequirement. Each locomotive may include a motor and air compressor foroperation of an air brake system, for example. Such compressors may bewater cooled. Air compressors on locomotives by EMD are typically cooledusing recirculated water from an engine compartment or engine-basedclosed system. For example, an intercooler is provided on the aircompressor and receives via internal passages the engine cooling water.Gardner Denver also produces examples of such air compressors that arecooled via engine coolant. Any thermal energy generated by aircompression may be transferred to the engine coolant for release to theatmosphere through radiators.

Because existing air compressors on locomotives are typically cooledusing recirculated engine coolant, temperatures of the engine coolantmay increase, resulting in lower efficiency and temperature control, andpossible lower performance of the air compressor.

SUMMARY

It is an aspect of this disclosure to provide an air compressor with aself-contained, liquid-cooled cooling system.

Another aspect provides a closed-loop cooling system including an aircompressor that includes at least one passage for a flow of coolanttherethrough to cool its parts. At least one temperature sensor islocated in the air compressor for measuring a temperature of thecoolant. The system also includes a pump for pumping an input flow ofcoolant into at least one passage of the air compressor and a heatexchanger for cooling an output flow of coolant from at least onepassage of the air compressor. A rate of flow of the coolant is based onthe temperature of the coolant measured by at least one temperaturesensor.

Another aspect provides a self-contained closed-loop cooling system fora vehicle. The system includes an air compressor operable to producecompressed air with at least one passage for flow of coolanttherethrough, a pump for pumping an input flow of coolant into the atleast one passage of the air compressor, and a heat exchanger forcooling an output flow of coolant from the at least one passage of theair compressor. The self-contained closed loop cooling system isindependent of an engine cooling system of the vehicle.

Yet another aspect provides a locomotive. The locomotive includes anengine, an engine cooling system, and a self-contained air compressorsystem. The compressor system includes an air compressor operable toproduce compressed air. The air compressor includes at least one passagefor flow of coolant therethrough. The compressor system also includes apump for pumping an input flow of coolant into the at least one passageof the air compressor, a heat exchanger for cooling an output flow ofcoolant from the at least one passage of the air compressor, and aplurality of fluid delivery lines connecting the air compressor, thepump, and the heat exchanger in a closed loop configuration for the flowof coolant therethrough. The self-contained air compressor system isseparate and not coupled to the engine cooling system.

Still yet another aspect provides a method of controlling a temperatureof an air compressor of a locomotive configured to receive and compressair from an air source. The air compressor has a passage for flow ofcoolant that is in closed communication with a pump and a heatexchanger. The method includes pumping coolant to the air compressorusing the pump to deliver coolant to the air compressor; passing theflow of coolant through the passage of the air compressor; outputtingcoolant from the passage of the air compressor to the heat exchanger;removing heat from the coolant with the heat exchanger; and deliveringthe coolant from the heat exchanger to the pump for pumping. Atemperature of the coolant in the passage is determined using at leastone temperature sensor located in the air compressor, and a rate of flowof the coolant is based on the temperature of the coolant.

Other features and advantages of the present invention will becomeapparent from the following detailed description, the accompanyingdrawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a train moving along a track having at least one locomotiveconfigured to utilize an embodiment of the present invention.

FIG. 2 shows a schematic view of an example locomotive configured to usea self-contained air compressor cooling system in accordance with anembodiment of the present invention.

FIG. 3 illustrates example devices or systems in a locomotive includinga self-contained air compressor cooling system.

FIG. 4 shows a diagram of the self-contained, compressor cooling systemin accordance with an embodiment.

FIG. 5 illustrates an example of an air compressor for use with theself-contained, compressor cooling system of FIG. 4, in accordance withan embodiment.

FIG. 6 shows a schematic diagram of air brake equipment that may utilizecompressed air from the air compressor in the locomotive, in accordancewith an embodiment.

DETAILED DESCRIPTION

Aspects of this disclosure provide for the replacement of an existingair compressor cooling system that typically uses engine water coolant,with a self-contained, closed loop system that is separate from and isnot coupled to the engine cooling system in a vehicle. Theself-contained cooling system is independent of the engine coolingsystem. Various aspects of the disclosure provide for improvements inefficiency and temperature control, among other features, of the aircompressor in a locomotive, thus resulting in performance optimizationof the air compressor within the locomotive.

Referring now more particularly to the drawings, FIG. 1 shows, in part,a train 100 that includes a series of containers 106 that may beprovided on cars 113 and pulled by one or more locomotives 102 (or alocomotive consist(s) within the length of the train 100) along a track104, to transport goods on land, for example. Wheels 108 of thelocomotives and cars 113 are pulled along spaced apart rails of thetrack 104 in a forward direction as indicated by arrow 112, for example.

FIG. 2 shows a schematic view of an example locomotive 102 configuredfor use with the self-contained air compressor cooling system 200, whichis further detailed below. The self-contained air compressor coolingsystem 200 may be located at the rear of a locomotive or a train, e.g.,behind an engine. The locomotive 102 includes any number of associatedsystems therein that may be used for operation of the locomotive or foroperation of the train, such as train 100. Air from the compressorsystem 200 may be supplied to an air brake system, a horn, an airstarter, sanders, windshield wipers, radar lens cleaning, and/or airoperated magnet valves, for example. As an example embodiment, thecompressor system's use with an air braking system is described below,but it is a non-limiting example.

FIG. 3 illustrates example devices or systems in a locomotive 102 whichincludes a self-contained air compressor cooling system 200. Included inthe locomotive, for example, is the self-contained air compressorcooling system 200, an engine 204 with an engine cooling system 206, airsource 208, and an air brake system 210 (and/or other system(s) that mayreceive compressed air from the self-contained air compressor coolingsystem 200). The self-contained air compressor cooling system 200 may beconfigured as a closed loop system.

FIG. 4 shows an illustrative diagram of the self-contained, closed loopair compressor cooling system 200, or “cooling system” as it may bereferred to hereinafter, for at least one air compressor 300, inaccordance with an embodiment. Also included in the cooling system 200are a pump 312 and a heat exchanger 314. A controller 310 and a fan 316are also included in the cooling system 200.

The self-contained cooling system 200 is associated with andcommunicates solely with the air compressor 300 for flowing coolantthrough at least one passage 307 of the air compressor 300 for heatrecovery to cool its parts. As the coolant or fluid circulates throughthe fluid circuit defined by the passage(s) 307, the temperature of theparts is cooled via heat transfer to the flowing coolant.

Throughout this disclosure, it should be understood that reference tothe self-contained air compressor cooling system 200, or cooling system200, refers to a system for an air compressor 300 of a locomotive 102.The cooling system 200 utilizes contained, circulating coolant for heattransfer and/or absorption of any thermal energy generated by the aircompressor 300 for release to the atmosphere (e.g., through radiators),without connection to or use of engine coolant or other coolant feed.The herein disclosed cooling system 200 may also be integrated into amodular package. In an embodiment, the self-contained cooling system 200for the air compressor 300 may be a retrofit system designed forconnection to an existing air compressor in a locomotive, such that uponconnection or installation to an air compressor, it may circulatecoolant in a contained, closed loop, while being subjected to alternatecooling and heating, without use of the engine coolant or other systemcoolant feed (e.g., wherein any valve or connection with a flow ofcoolant from the engine cooling system is closed or disconnected uponretrofit of the cooling system 200 to the air compressor 300). The flowof coolant is distributed without contact to atmospheric or ambient airvia fluid delivery lines, for example, through the cooling system 200.

The air compressor 300 receives and compresses air from an air source208. Generally, the air source 208 may be ambient or atmospheric air. Tooperate the air compressor 300, a power source 304 is provided and iscoupled to the air compressor 300 for driving the air compressor 300 toproduce compressed air. The power source 304 may be provided in thelocomotive 102, for example. The compressor 300 may be connected to thepower source 304 via a drive shaft 303, for example, or the drive shaft303 itself may be considered the power source 304. In an embodiment, thepower source 304 is a motor or engine. An engine for driving the aircompressor 300 may be the main power source for the locomotive 102, forexample. In an embodiment, the engine may comprise the power source 304.That is, the air compressor 300 may be driven from the locomotive'sengine (e.g., diesel engine) through drive shaft 303 and couplings. Theengine may rotate the drive shaft 303 to drive various devices andsystems needed to power the locomotive 102 (e.g., electricity generatoror alternator to move the train), including the air compressor 300.

The air compressor 300 is operable to produce a flow of compressed airfor locomotive applications. Air is supplied via an air intake line 305from the air source 208 into an air inlet 306 (or inlets) of the aircompressor 300 during operation. Air is compressed by the air compressorand the compressed air is output via an air outlet 308 (or outlets) andprovided via a compressed air delivery line 309 to an associated systemof the locomotive, e.g., to an air brake system 210, such as shown inFIG. 6.

The air compressor 300 utilized in the example locomotive is not limitedby type. In an embodiment, the air compressor is a two-stage,reciprocating type air compressor. In an embodiment, the air compressorhas three stages of cylinders arranged in a pattern, with two lowpressure cylinders and one high pressure cylinder. In an embodiment, theair compressor is a two stage, three cylinder W configuration as shownin FIG. 5. In another embodiment, the air compressor comprises fourcylinders.

The air compressor 300 may act as a single stage air compressor. In anembodiment, the air compressor 300 is multi stage compressor.

In accordance with an embodiment, the air compressor 300 comprises anair compressor manufactured and/or distributed by Gardner Denver,including, but not limited to, three or four cylinder models.

The air compressor 300 may be a reciprocating compressor, rotary screwcompressor, or a centrifugal compressor. The air compressor 300 maycomprise any number of cylinders and pistons. The air compressor 300 mayalso include an intercooler assembly for reducing the temperature of theexiting or output compressed air. These and other parts of thecompressor, e.g., crankcase, filters, pump, valves, gauges, etc. areunderstood by those of ordinary skill in the art, and thus are notexplained in detail herein. Further, the movement and implementation ofthose parts, e.g., strokes of the cylinder, and any cycle of operationmay not be described in detail herein, but are understood by one ofordinary skill in the art.

However, as an example, general operation of a two stage, three cylinderair compressor 300 may be understood as follows: atmospheric air isdelivered from air intake filters of the air source 208 through an openinlet valve (at air inlet 306) of the air compressor 300 into the lowpressure cylinders for compression. The air is cooled and is directed tothe high pressure cylinder for further compression, via an intercooler(e.g., a radiator between the low and high pressure cylinders). Theintercooler may include a jacket for the coolant passage. Then thecompressed, pressurized air is directed or exhausted through an outletvalve (at air outlet 308) to reservoirs and delivered to the associatedsystem via the output line 309 (e.g., in an air brake system 210,compressed air is directed to a reservoir for distribution to brakecylinders/pistons to develop mechanical brake power).

The air compressor 300 includes at least one passage 307 for a flow ofcoolant therethrough to cool its parts. Rather than receiving enginecooling water in its internal passages to cool its intercooler assembly,heat generated from the air being discharged from the cylinders istransferred to coolant circulating in the at least one passage 307, andis released to the atmosphere through fan 316 and/or heat exchanger 314,for example. The cooling of the compressor parts improves the volumetricefficiency of the air compressor 300. In an embodiment, the intercoolerincludes a fan which increases the cooling efficiency.

Fluid delivery lines 318, 324, and 330 connect the air compressor 300,the pump 312, and the heat exchanger 314 in a closed loop configurationfor the flow of coolant therethrough. The flow of coolant may bedistributed via the fluid delivery lines 318, 324, and 330 through thepump 312, heat exchanger 314, and air compressor 300 without contact toatmospheric/ambient air and without interaction to any cooling systemfor the engine of the locomotive. Reference to types of fluid deliverylines are not intended to be limited; the pump 312, air compressor 300,and heat exchanger 314 may be connected via pipes, tubes, and/orconduits, for example.

At least one controller 310 or a control system may be provided in theself-contained cooling system 200 for controlling and communicating withthe associated parts, e.g., pump 312, heat exchanger 314, fan 316, andvalve 334 along the fluid delivery lines 318, 324, and 330. Thecontroller 310 may output and receive information and/or data associatedwith the cooling system 200, including the air compressor 300, as wellas any number of other systems, including remote systems or devices notinstalled on the locomotive 102. The controller 310 may be amicrocontroller or microprocessor, for example. Any reference to acontroller 310 herein should be understood to correspond to a device ora system that may include one or more controllers or processors. Asdescribed later, the controller 310 may be used to control a rate offlow of the coolant throughout the fluid delivery lines 318, 324, and330 and/or the at least one passage 307 of the compressor. For example,the controller 310 may be used to control rate of flow from the pump312. The controller 310 may also be used to adjust the speed of the fan316, for example. As also described later, the controller 310 mayreceive temperature related to the coolant from one or more temperaturesensors 340, 342 provided in the air compressor 300. The temperaturedata may be used by the controller 310 to adjust operation of thecooling system 200. For example, the rate of flow of the coolant may beadjusted based on temperature data. Based on the temperature data,controller 310 may transmit one or more control signals to the pump 312to vary the rate of flow provided by the pump 312.

The pump 312 pumps an input flow of coolant into the at least onepassage 307 of the air compressor 300. As shown in FIG. 4, fluiddelivery line 318 is an input line connected between an outlet 338 ofthe pump 312 and a coolant inlet 320 of the air compressor 300 fordelivery of the pumped coolant to the air compressor 300. The pump 312is provided upstream of the air compressor 300 and delivers coolant thatis cooled by the heat exchanger 314 to absorb heat from the parts of theair compressor 300. The pump 312 may be moved between an open position(e.g., ON), a closed position (e.g., OFF), and positions therebetween tocontrol the amount or rate of flow of coolant therefrom, for example(e.g., via controller 310).

An optional control valve 334 may be provided on the input fluiddelivery line 318 that is configured for movement (e.g., via controlprovided by the controller 310) between an open position, a closedposition, and positions therebetween, to control (e.g., allow or limitor prevent) the amount or rate of input flow of the pumped coolant beingdelivered from or by the pump 312 to the at least one passage 307 of theair compressor 300, for example. Although only one coolant control valveis shown in FIG. 4, any number of valves may be provided along the linesor associated with the pieces of equipment in the disclosed closed loopdesign. In an embodiment, control valve 334 is provided in line with andclosest to a point of actuation relative to the pump 312. In anembodiment, control valve 334 is provided in line with and closest to apoint of actuation relative to the air compressor 300.

Operation of the pump 312 is generally known and thus not described indetail herein. The type of pump used in the cooling system 200 is notlimiting. In an embodiment, the pump 312 is a 74 volt DC inverter drivenpump.

The heat exchanger 314 cools an output flow of coolant received from theat least one passage 307 of the air compressor 300. The fluid deliveryline 324 is an output line connected between a coolant outlet 322 of theair compressor 300 and an inlet 326 of the heat exchanger 314 fordelivery of the output flow of coolant from the air compressor 300 tothe heat exchanger for cooling.

The heat exchanger 314 is configured to cool the output flow of coolantas it runs through, so that the temperature of the coolant is decreasedand may be used (pumped) again through the air compressor 300 forcooling. Since the process of compressing air may produce heat, thecirculating coolant increases in temperature as the heat is transferredthereto. Thus, the output coolant is higher in temperature than theinput coolant. Such heat may not only increase the temperature of thecompressed air but also any fluids, such as oil, used for lubricatingand sealing parts of the compressor. Accordingly, the heat exchanger isconfigured to receive the higher temperature output coolant downstreamfrom the air compressor 300 to reduce the temperature of the coolant.

The fan 316 provides air flow through and/or across the heat exchanger314. The fan 316 moves air across the heat exchanger 314, as shown byarrows 332 in FIG. 4, to cool the output flow of coolant received fromthe air compressor 300. The fan 316 is driven at a speed by a motor thatis included in the locomotive, or that is separately provided for thefan itself. The fan 316 may be moved between an ON position, an OFFposition, and positions therebetween to control the amount or rate ofair flow, for example (e.g., via controller 310).

Operation of the heat exchanger 314 and fan 316 are generally known andthus not described in detail herein. The type of heat exchanger 314 orfan 316 used in the cooling system 200 is not limiting. In anembodiment, the fan 316 is a 74 volt DC inverter driven cooling fan. Theheat exchanger 314 may be sized and/or configured based on heatrejection of the air compressor 300. The heat exchanger 314 may also usemechanically bonded tubes.

After coolant flows through the heat exchanger 314, it is delivered backto the pump 312. Fluid delivery line 330 is an intermediate lineconnected between the heat exchanger 314 and the pump 312 for deliveryof the cooled output flow of coolant from the outlet 328 of the heatexchanger 314 to the inlet 336 of the pump 312. The pump 312 may thendeliver the cooled output flow of coolant to the air compressor 300.

The self-contained cooling system 200 may also include one or moresensors. The one or more sensors may be one or more temperature sensors340, 342, for example, or a combination of one or more different typesof sensors. As an example, a first temperature sensor 340 may beprovided adjacent to the coolant inlet 320 of the air compressor 300,e.g., on fluid delivery line 318. A second temperature sensor 342 may beprovided adjacent to the coolant outlet 322, e.g., on fluid deliveryline 334. The temperature sensors 340, 342 are used to measure or readthe temperature of the coolant. In an embodiment, at least onetemperature sensor 340 and/or 342 is located in the air compressor 300.

As shown in FIG. 4, in an embodiment, both temperature sensors 340, 342are located in the air compressor 300. The first temperature sensor 340is located at an inlet or input of the passage 307 in the air compressor300 and the second temperature sensor 342 is located at an outlet oroutput of the passage 307 in the air compressor 300. A first temperaturereading of the coolant may be generated by the first temperature sensor340 and a second temperature reading of the coolant may be generated bythe second temperature sensor 342. One or both of the temperaturereadings may be used to determine a temperature of the coolant in thecooling system 200. For example, in an embodiment, an average of the tworeadings measured by the temperature sensors 340, 342 may be computedand used to determine or measure the temperature of the coolant.

The location and use of the illustrated temperature sensors 340, 342 asshown in FIG. 4 is an example only. Although not shown, a thirdtemperature sensor may be provided on the intermediate fluid deliveryline 330. Data or readings of the temperature of the coolant measured bythe third temperature sensor may be used to determine a temperature oraverage temperature of the coolant in the cooling system 200.

In accordance with an embodiment, a rate of flow of coolant (e.g., aspumped by pump 312) is based on the temperature of the coolant measuredby the one or more of the temperature sensors 340, 342. In accordancewith an embodiment, a speed of the fan 316 (e.g., as provided by amotor) is based on the temperature of the coolant measured by the one ormore of the temperature sensors 340, 342 and/or a third temperaturesensor. The temperature sensors 340, 342 and/or a third temperaturesensor may be utilized to determine if the temperature of thecirculating or flowing fluid and/or fan speed is adequate, or ifadjustments to the flow rate of the coolant, and/or to the fan speed,for example, need to be made to any of the devices or parts of thesystem (e.g., the fan 316 and/or pump 312 and/or control valve 334) toprovide the desired cooling to the air compressor 300.

As previously noted, the controller 310 controls the operation of atleast the cooling system 200 disclosed herein. The controller 310 maycontrol the operation of the air compressor 300 as well as the operationof the parts (e.g., pump 312, heat exchanger 314) used for cooling theair compressor 300.

In an embodiment, the controller 310 may be configured to communicatewith the air compressor 300, the pump 312, the heat exchanger 314, andthe fan 316 in the cooling system 200. The controller 310 may monitorand/or communicate with sensors (e.g., temperature sensors 340, 342) andany valves or controls (e.g., control valve 334 provided in the system).In an embodiment, the temperature sensors 340, 342 are communicativelycoupled to with the controller 310 to provide temperature data from thecoolant inlet 320 and outlet 322 of the air compressor 300. Thecontroller 310 may use such data to adjust the coolant temperature thatis flowing through the fluid delivery lines 318, 324, 330. For example,in an embodiment, the controller 310 is configured to cycle the coolantcirculation pump 312 ON and OFF or vary the rate of flow of the coolantbased on coolant temperature (e.g., as measured by the one or moretemperature sensors 340, 342 and/or third temperature sensor). In anembodiment, the controller 310 is configured to instruct the fan 316 toincrease or decrease its speed based on the coolant temperature measuredby at least one of the sensors 340, 342 and/or a third temperaturesensor, and thus increase or decrease the flow of cooling air on theheat exchanger 314, to facilitate a change in the temperature of thecoolant that is output from the heat exchanger 314. The controller 310may turn the fan 316 ON or OFF. In an embodiment, the controller 310 isconfigured to adjust a rate of flow of coolant through a plurality offluid delivery lines 318, 324, 330 based on the temperature of thecoolant, e.g., via adjustment of the rate at which the pump 312 pumpsthe coolant, or via adjustment of valves, such as valve 334, to an openposition or a closed position, and/or in a position therebetween, toopen, limit, adjust, and/or close flow of the coolant in the one or morefluid delivery lines 318, 324, 330. The controller 310 may control thepump 312 using one or more control signals transmitted from thecontroller 310 to the pump 312.

The controller 310 may also be used to limit circulation or flow ofcoolant throughout the cooling system 200. For example, when cooling isnot required, e.g., when the air compressor 300 is not in operation oris not producing heat, the coolant will not be circulated.

The controller may be further used, as shown schematically in FIG. 3, tocontrol the operation of the engine 204 of the locomotive, the enginecooling system 206, the air brake system 210, air source 208, and thelike, within the locomotive 102.

The type of coolant used with the air compressor cooling system may beany type or number of coolants and is not intended to be limiting. In anembodiment, the coolant is a fluid. In an embodiment, the coolant iswater. In an embodiment, the coolant is a propylene glycol solution,also referred to as “glycol.”

Accordingly, when the air compressor 300 is in operation and receivingand then compressing air, the temperature of the air compressor 300 ofthe locomotive may be controlled. For example, during such operation,the method includes pumping coolant to the air compressor 300 using thepump 312 to deliver coolant to the air compressor 300, passing the flowof coolant through the at least one passage 307 of the air compressor300, outputting coolant from the at least one passage 307 of the aircompressor 300 to the heat exchanger 314, removing the heat from thecoolant with the heat exchanger 314, and directing the coolant from theheat exchanger 314 to the pump 312 for pumping. A temperature of thecoolant in the passage 307 is determined using at least one temperaturesensor 340 and/or 342 located in the air compressor 300, and a rate offlow of the coolant through the pump 312, air compressor 300, and heatexchanger 314 is controlled based on the temperature of the coolant asdetected by the at least one temperature sensor 340 and/or 342. Forexample, the rate of flow of the coolant may increase as the temperatureof the coolant increases to better facilitate removal of the heat of theheat exchanger 314. In an embodiment, the temperature of the coolant isdetermined by computing, e.g., using the controller 310 or other type ofprocessing device, the average of a first temperature reading generatedby the first temperature sensor 340 and a second temperature readinggenerated by the second temperature sensor 342.

The disclosed cooling system 200 provides sufficient cost savings to thelocomotive industry since rebuilding an air compressor is expensive(e.g., the cost to rebuild may be several thousands of dollars).Further, air compressors that are damaged (e.g., due to freeze damage)typically crack the cooling jacket in the cylinder liner, which furtheradds to any rebuild cost. Other unscheduled or unanticipated failuresalso add to replacement or rebuild costs.

By replacing existing air compressor cooling systems that typicallyutilize engine water coolant with the herein disclosed self-containedcooling system 200 (that is separate from the engine cooling system),efficiency and temperature control are improved, resulting inperformance optimization of the air compressor 300.

In addition to cooling and/or substantially maintaining a temperature ofliquid cooled air compressors, and substantially reducing and/oreliminating freeze damage to liquid cooled air compressors (and/or partsthereof) as noted above, the herein disclosed cooling system 200 alsoeliminates thermal energy added to an engine's cooling system (which istypically found in the prior art when using recirculated engine coolantto cool an air compressor). Accordingly, the temperature of the enginecoolant may be reduced since compressor cooling is separatelymaintained.

Further, the life of the air compressor 300 itself may be extended. Thepresence of cooler temperatures in the cooling system 200 also reducesoil consumption and provides drier air and, when used with an air brakesystem, improves air brake reliability. Moreover, little, if any,evaporation occurs. Use of this cooling system with the air compressoralso results in a compressor that is less susceptible to oil depositsand corrosion on air compressor parts.

As previously mentioned, the compressed air output from the aircompressor 300 may be used with any number of systems associated withthe locomotive, or the train itself. FIG. 6 shows a schematic diagram ofequipment in an air brake system 210 that may utilize such compressedair from the air compressor 300. The air compressor 300 may be designedto reduce volume of air and deliver compressed air at a proper pressurelevel.

FIG. 6 shows the air compressor 300 connected via a delivery line to amain reservoir 402 or storage tank for the compressed air for braking(and other pneumatic systems). The main reservoir 402 is connected to adriver's brake valve 406. The driver's brake valve 406 allows a driver(e.g., conductor) to control the brake or provide braking action of thebrakes on the wheels of the locomotive 102. A feed valve 410 isconnected between the main reservoir 402 and a brake pipe 412 when thebrake is operating and may be set to a specific operating pressure. Theequalizing reservoir 408 may be used to aid in providing appropriatepressure. The brake pipe 412 may run the length of the train to transmitthe variations in pressure required to control the brake on each car 113or locomotive 102 along the length of the train, for example. It may beconnected between locomotives by flexible hoses designed for couplingand uncoupling.

Brake cylinder(s) 416 are provided on the locomotives and controlled viamovement of the piston contained inside the cylinder(s) 416. The pistonapplies brake blocks 418 to the wheels 108. The piston inside each brakecylinder 416 moves in accordance with the change in air pressure in thecylinder 416. As the air pressure changes, the application or release ofthe brake blocks 418 is controlled by the actuation of the brakepistons.

In an embodiment, an auxiliary reservoir 404 may be connected to thebrake pipe 412 on an opposite side of the brake cylinder 416. Theauxiliary reservoir 404 may be used to ensure there is a source of airavailable to operate the brake. A triple valve or distributor 414 mayalso be provided to control the flow of air into and out of theauxiliary reservoir 404. For example, the triple valve or distributor414 may be used to release the brake, to apply the brake, and/or to holdthe brake at its current level of application.

Although FIG. 6 illustratively describes use of the air compressor 300with an air brake system 210, it should be understood that compressedair from air compressor 300 may also be used to operate an airsuspension system and/or auxiliary systems associated with a locomotiveor train, such as, but not limited to, a horn, bell, doors, etc. Thecompressed air from the air compressor 300 may be delivered to otherpower systems in addition, or alternatively to, the air brake system210.

Further, the type of locomotive 102 that utilizes the self-containedcooling system 200 is not intended to be limiting. The location of thelocomotive 102 utilizing the cooling system 200 in a train 100 is alsonot limiting. The cooling system 200 may be provided in the locomotive102 that is in a leading configuration, trailing configuration, or amonga series of locomotives. For example, as shown in FIG. 1, one or more ofthe locomotives 102 in the train 100 may include the cooling system 200as disclosed herein. In an embodiment, all of the locomotives 102provided along a length of the train 100 may include the cooling system200 as described herein. Furthermore, the disclosed cooling system 200may be used in one or more locomotives 102 in any number or types oftrains, including, but not limited to high-speed trains and multipleunit (MU) trains, light rail vehicles, and/or subway vehicles.

Again, the disclosed cooling system 200 should not be limited for usewith the described air brake system 210. For example, output air fromthe air compressor 300 may be used with a horn, an air starter, sanders,windshield wipers, radar lens cleaning, and/or air operated magnetvalves. Moreover, it should be understood that the disclosed coolingsystem 200 may be manufactured, distributed, and/or provided as apackage designed for retrofitting to an existing air compressor on alocomotive (e.g., attaching or configuring to a previously manufacturedair compressor), or as a self-contained system comprising a combinationof the air compressor and the cooling system in a single housing. Thecooling system 200 may also be used in new locomotives, and it may beinstalled and/or used to replace existing systems.

Moreover, although the cooling system 200 has been described for usethroughout this disclosure with a locomotive, it should be understood toone of ordinary skill in the art that the cooling system 200 asdisclosed herein may be used in other types of vehicles, and thus itsapplication is not limited for use with a locomotive.

While the principles of the disclosure have been made clear in theillustrative embodiments set forth above, it will be apparent to thoseskilled in the art that various modifications may be made to thestructure, arrangement, proportion, elements, materials, and componentsused in the practice of the disclosure.

It will thus be seen that the features of this disclosure have beenfully and effectively accomplished. It will be realized, however, thatthe foregoing preferred embodiments have been shown and described forthe purpose of illustrating the functional and structural principles ofthis disclosure and are subject to change without departure from suchprinciples. Therefore, this disclosure includes all modificationsencompassed within the spirit and scope of the following claims.

What is claimed is:
 1. A closed-loop cooling system comprising: an aircompressor including at least one passage for a flow of coolanttherethrough to cool its parts; at least one temperature sensor locatedin the air compressor for measuring a temperature of the coolant; a pumpfor pumping an input flow of coolant into the at least one passage ofthe air compressor; and a heat exchanger for cooling an output flow ofcoolant from the at least one passage of the air compressor, wherein arate of flow of the coolant is based on the temperature of the coolantmeasured by the at least one temperature sensor.
 2. The system accordingto claim 1, further comprising a fan for moving air across the heatexchanger to cool the output flow of coolant wherein a speed of the fanis based on the temperature of the coolant measured by the at least onetemperature sensor.
 3. The system according to claim 1, wherein the flowof coolant is distributed via the plurality of fluid delivery linesconnecting the pump, heat exchanger, and air compressor.
 4. The systemaccording to claim 3, wherein the plurality of fluid delivery linescomprises: an input line connected between the pump and the aircompressor for delivery of the input flow of coolant from the pump intothe at least one passage of the air compressor; an output line connectedbetween the air compressor and the heat exchanger for delivery of theoutput flow of coolant from the at least one passage of the aircompressor to the heat exchanger; and an intermediate line connectedbetween the heat exchanger and the pump for delivery of the cooledoutput flow of coolant from the heat exchanger to the pump.
 5. Thesystem according to claim 1, wherein the associated system is an airbrake system.
 6. The system according to claim 4, further comprising acontrol valve situated along the input line configured for movementbetween open and closed positions to allow or limit the input flow ofcoolant into the at least one passage of the air compressor.
 7. Thesystem according to claim 1, further comprising a controller configuredto adjust the rate of flow of the coolant based on the temperature ofthe coolant.
 8. The system according to claim 1, wherein the coolant ispolypropylene glycol.
 9. A self-contained closed-loop cooling system fora vehicle comprising: an air compressor operable to produce compressedair, the air compressor including at least one passage for flow ofcoolant therethrough; a pump for pumping an input flow of coolant intothe at least one passage of the air compressor; a heat exchanger forcooling an output flow of coolant from the at least one passage of theair compressor; and wherein the self-contained closed-loop coolingsystem is independent of an engine cooling system of the vehicle. 10.The system according to claim 9, further comprising a fan for moving airacross the heat exchanger to cool the output flow of coolant.
 11. Thesystem according to claim 9, wherein the flow of coolant is distributedvia the plurality of fluid delivery lines connecting the pump, heatexchanger, and air compressor.
 12. The system according to claim 11,wherein the plurality of fluid delivery lines comprises: an input lineconnected between the pump and the air compressor for delivery of theinput flow of coolant from the pump into the at least one passage of theair compressor; an output line connected between the air compressor andthe heat exchanger for delivery of the output flow of coolant from theat least one passage of the air compressor to the heat exchanger; and anintermediate line connected between the heat exchanger and the pump fordelivery of the cooled output flow of coolant from the heat exchanger tothe pump.
 13. The system according to claim 9, further comprising acontroller configured to at least adjust a rate of flow of the coolantbased on the temperature of the coolant.
 14. The system according toclaim 10, wherein a speed of the fan is based on a temperature of thecoolant measured by at least one temperature sensor.
 15. The systemaccording to claim 9, further comprising at least one temperature sensorlocated in the at least one passage of the air compressor for measuringa temperature of the coolant, wherein a rate of flow of the coolant isbased on the temperature of the coolant measured by the at least onetemperature sensor.
 16. The system according to claim 9, wherein thecoolant is polypropylene glycol.
 17. A locomotive comprising: an engine;an engine cooling system; and a self-contained air compressor systemcomprising: an air compressor operable to produce compressed air, theair compressor including at least one passage for flow of coolanttherethrough; a pump for pumping an input flow of coolant into the atleast one passage of the air compressor; a heat exchanger for cooling anoutput flow of coolant from the at least one passage of the aircompressor; and a plurality of fluid delivery lines connecting the aircompressor, the pump, and the heat exchanger in a closed loopconfiguration for the flow of coolant therethrough; wherein theself-contained air compressor system is separate and not coupled to theengine cooling system.
 18. The locomotive according to claim 17, furthercomprising a controller configured to at least adjust a rate of flow ofthe flow of coolant based on the temperature of the coolant.
 19. Thelocomotive according to claim 17, further comprising a fan for movingair across the heat exchanger to cool the output flow of coolant. 20.The locomotive according to claim 19, further comprising at least onetemperature sensor located in the at least one passage of the aircompressor for measuring a temperature of the coolant, wherein a rate offlow of the coolant and a speed of the fan are based on the temperatureof the coolant measured by the at least one temperature sensor.
 21. Amethod of controlling a temperature of an air compressor of a locomotiveconfigured to receive and compress air from an air source, the aircompressor comprising a passage for flow of coolant therethrough, thepassage in closed communication with a pump and a heat exchanger; themethod comprising: pumping coolant to the air compressor using the pumpto deliver coolant to the air compressor; passing the flow of coolantthrough the passage of the air compressor; outputting coolant from thepassage of the air compressor to the heat exchanger; removing heat fromthe coolant with the heat exchanger; and delivering the coolant from theheat exchanger to the pump for pumping, wherein a temperature of thecoolant in the passage is determined using at least one temperaturesensor located in the air compressor and wherein a rate of flow of thecoolant is based on the temperature of the coolant.
 22. The method ofclaim 21, wherein the at least one temperature sensor comprises a firsttemperature sensor located at an inlet of the passage for generating afirst temperature reading and a second temperature sensor located at anoutput of the passage for generating a second temperature reading. 23.The method of claim 22, wherein the temperature of the coolant isdetermined by computing the average of the first temperature readinggenerated by the first temperature sensor and the second temperaturereading generated by the second temperature sensor.